A study of the toxic perfluorinated chemicals found in water near U.S. military airports has measured drinking-water contamination at an undisclosed site at levels more than 100 times higher than a federal health advisory limit.

Colorado School of Mines researchers also found that the carbon filters being installed by hard-hit communities — including Fountain and Widefield, south of Peterson Air Force Base — fail to fully remove the chemicals, according to a peer-reviewed study to be published Tuesday in the journal Environmental Science and Technology.

The city water supply where perfluorinated chemical (PFC) contamination measured 11,000 parts per trillion (ppt) and 33,000 ppt – far above the EPA health advisory limit of 70 ppt – “was in a water supply near a military base” where firefighters had used aqueous film-forming foam (AFFF), a primary source of contamination, Higgins said. The samples were taken “from a wellhead that was feeding into the water supply.”